Observation of small metastable multiply charged Csl clusters embedded inside rare gas clusters

Medium size Kr and Ar clusters (N) similar to 200 - 400 were used to pick u p and aggregate CsI molecules. By varying the number of pick-up events it w as possible to change the size of the guest cluster and the thickness of th e rare gas coverage around the alkali halide cluster. "Soft" single (multip le) ionisation of the alkali halide core was achieved via charge transfer f rom the primary ionised rare gas shell. It turns out that the rare gas shel l controls the vibrational relaxation of CsI cluster ions. Due to cooling b y the rare gas shell shallow metastable states of multiply charged Csf clus ters can be populated and detected. Clusters as small as Cs5I32+, Cs6I52+, Cs13I133+ and Cs17I143+ could be observed for the first time. The abundance of these multiply charged clusters steeply decreases if the thickness of r are gas shell shrinks.